Flue structure for regenerative stoves



` 2 sheets-sheet 1 July 22, 1930. A. c. NELSON FLUE STRUCTURE FORREGENERATIVE STOVS Filed Aug. 1o, 1928 July 22, 1930.

A. c. NELSON FLUE STRUCTURE FOR REGENERATIVE STOVES 2 Sheets-Sheet 2Filed Aug. 10, 1928 6' Naso/v Arme/VHS AU'e-o P| 9 WM www lm 50 Amongthe objects of Patented y July 22, 1930 UNITEDSTATES vALFRED c. Nansen,or 'Lnrrrzvvoon OHIO `FLUE STRUCTURE FOR nEGnivEnATivE S'rlovEs fApplication led VAugust 10, 19283. Serial 110,298,790. y

My invention relatesto the type of regenerative heatjeXchange apparatusof which blast furnace hot blast Vstoves and openhearth furnaceregenerators are common y forms.. In'apparatus of this type gases areburned and passed over or throu h some refractory material, such `asfire brick. A Zhen this refractory material is suiliciently heated theflow of hot gas is shut off and cool airis 10 forced `through intheopposite direction. Ihe air is heatedby contact as it passes by the hotrefractory `material and continues to flow until a certain amount of theheat left in the refractory material vbythe hot gases is ab isorbed.`The cycle `is then repeated,`the hot gases heating the refractorymaterial and e the cool air absorbing the heat, the refractory materialbeing alternately heated by the hot gases and cooled by the air or gaswhose temperaturefis to be increased.

In this specification and in the drawings I have shown and described myinvention as applied toa common form of'hot blast stove nsedinconnection with blast furnaces for reducing iron ore to iron.v In thistype of `stove the gases from the top of the blast furnace are conductedto the stove where they are'burne d,the Vhot burning gases passing bythe refractory brick for a certain length of Sotime. The gaskis thenshut off and air is forced through the heated checker-work of brickandrinto the blast furnace, furnishing the heated airrequired for thereduction of the ore. In this way the gas` resulting from the operationof the blast furnace is utilized to pre-heat the air'. 'Several separatehotblast stoves are used` inxconnection with one blast furnace so thatwhile one is furnishing heated air to thefurnace the Others are being 40heated by'burning waste gas from thef blast furnace in `the combustionchamber ofthe stove. In' thisway a continuous supply'of pre-heatedair isobtained. In case ofan open hearth' regenerator the waste heat Vfrom thefurnace heats the regenerators directly (the open hearth furnace vitselfacting as a comv bustion chamber for-the waste gases) and the ereversals occurmorefrequently than ine-blast furnace practice.

i tically.' adjacent courses of brick separatedto my invention are :f

The *provision of an improved method `of laying up brick for `the fluestructure Of re-` generative stoves by` virtue of which 'each brick inthe flue structurecan expand without disturbing its neighbor; theprovision of alflue structure made of rectangular brickin which theindividual flueshave a much greater surface area in proportion totheircrosssection area thanV other forms which have been heretoforeproposed the provision of a checkerwork structure made `of `rectangularY Y brick whichmay be easily and quickl laid upand in which all jointsbetweenbric s are bonded by the bricks in the'adjacent courses; theprovision ofl a checker-brick structure in which there is no Waste' orinactive brick. the brick being'so laid that the walls between all thenues are of uniform thickness, and the provisionV of a flue structurehaving flues a cross-shaped on a plane erpendicular to theirlongitudinal axes. ther advantages of my invention over other typesofiue struc` tures will be evident from the drawings and specification.e

I do not limit my invention to the specific form shown in thisspecification as it -willbe clear to those skilled in the art that itmay be adapted to other types of regenerative heat exchange apparatusand embodiedin structures other than that shown.`

Referringto the drawings y f,

Fig. 1 is a vertical section through acommon type of hot blast stove,the lues of which are built in accordance with my invention.

Fig." 2 isan enlarged view taken'between lines 2A, 2A and 2B, 2B in Figi`1,sh"o\` ving stove shownin Fig. 1.

Fig. 3 is a plan sectionl ofmyimproved stove taken on line 3 3 of Figs.1 and 2.

Fig. Itis' an enlarged plan view ofia por- `several courses of brickofaportion of the ofbrick. il

` tion of the flue structure showing two courses Fig. 5 .is aperspective view of twover-V show how the bricks offene course Overlapthose of theadjacent course. `f

The `hot blast stove shown in Fig." 1" is thetypeused in connection with`blast -furnaces. When thestove is in 'operation the blastfuxf nace gasenters the bottoni of the combustion chamber l through the pipe 2.V Thegas burns in the chamber l and the dome 3 and passes down through therefractory brick iiues 4 and out the chimney 5. After the checkerbrickiue structure is sulhciently hea-ted the gas is shut ott and air ispassed through the stove inthe opposite direction.` It ente-rs, at thebottoni and passes up through the heated flues 4, then dowli through thecombustion` chamber l and out at the bottom of the com# bustion chamber.The stove has a steel shell 6 and a lining'7 of refractory material. vAsshown in Figs. Band 4the flues 4 made in accordance with my inventionare vcrossshaped in horizont-al section.- gFlue structuies which havebeen built prior V"to my, invention havek been of square,frectangulai,or round shape iii-horizontal cross-section. Y

My invention provides Va methodfor laying up crossshaped flue structuresfrom standard rectangular brick. As shown 'inFi`g. 3. two sizes ofbrickare used. Bricks` 9 may be considered to be 9X 3'. X4 and bricksyl0 to be 6 X BX 4-. `The bricks, of course,

` lower course appears on'rthc left and theA up-v pery course on therright. On,` theright the lowercourse is shown under .the ,upper-course,in dotted lines. Aswill be 'seen from rthe drawings the lower courseconsists of ldouble rowsof 9 X 3 ,brick 9 laidparallel and l2 apart'.The bricks in. each single row of' these double rows are spacedaparte/admise... three inches and the three-incli-openings-are bridgedby the bricks in the adj aeentgsingle row of spaced-apartY bricks.ABetween the Y' .s by .brick 1 il".

double rows of spacedfapart 95'` 3X 3:bricks 9 are laidA the 6, X8bricks lO. These are placedwith their longitudinal ,aXesat 9,00 to thelongitudinal yaXes of `the double rows of 9 X 3 bricks 9 and arestaggered so that each Voverlapsfthe adjacent brick three inches. These'6, Xl 3'( bricks l0 .form zig-zag rows between the spacedapartdouble.rowsv ofv Q X13brick egna-nd, asis elearlyshownfin Fig. 3,fcomplete thewalls between the rcrossshapedflue-openings 4. '-,Th'ese cross-shapeddue l(menings .4 .are all off'the ,same` size,- eachz of their anglesvbeing 900 and each ofsltheir sidesfS bei-ng, three Vvinchesilo'ng. Y..They are arranged -in diagonal -.i -ows and are so spaced apart'. that jthe --center line` l-l, 1' Fig.. 4, of the bricks is alwaysequidistantfromthesurface;v oft-,wo` adjacent nue ropienings. j 4.Thusif each flue-opening iSiconsidered toz be surrounded hck, tl1erexw11 be.eepartot the? refractory material which is so far from a flue surfacethat it is inefiicient in absorbing and giving off heat. This is animportaut advantage of my invention as the regenerator is much moreeliicient when the bricks up in YeXactly the same way and of the sainesize bricks as the course below. AHowever, inf

order that the joints between the bricks may be bondedrand each bricknotl merely piled directly on top of the corresponding brick in thecourse below, the longitudinal double rows of 9 XfQbricks 9vare laid ontop of the 6 X 3 bricks l0` of the course below and midway between the;double longitudinal rows of 9l X 8 bricks 9 ofthe course below. Thesedouble longitudinal rows of 9 X 3' bricks l() are laid .parallel inallthe courses. In this Vway the cross-shaped flue openings of the uppercourse correspond with those of the lower course` andeach joint in thelower course is coveredby a brick in the upper course.

Fig. 5 of the drawings shows two'adjacent courses of brick inperspective. The courses have been separated to show the individualbricks inoie clearly. The method of laying up the bricks so that eachcourse is bonded by 1 the adjacent courses can be ,clearlyV seen.

, Several of' the bricks in the upper course have been `projecteddown toshowV wherethey would be placed onv the lower course ii' the courseswere not separated, for instance the Vbricks 9 wouldfcover the shadedarea 9' and Vthebricks lOv-'ould cover the shaded area 'The entire fluestructure of the stove is built upasabove described, as many courses ywouldnet provide a bond between4 the different courses. IThe.bondingwhich is very advantageous `in strengthening vthe. Aentire structure isobtained as 4above described*A and consists of merely".shiftingthc'rposition of everywother.course..--.All the courses when 4 1consideredy separately vare identical. y ,-My torni of .flueis superiortoother forms. -itflias a much greater surface area ,of

in that j brick inproporti/on tothecrossesection area..

canbe shownbvassuming that the lues i s fownl Fig; Sottile .drawings arelaid upv of bricksthree inches wide. y that v.each,ofthe .surfaces- Sjofthe, fines are It is evident three inches long and the cross-sectionarea v of a Hue is 45 square inches.

If the bricks are four inches deep the surface area of a Hue one brickhigh will be 3 x 4 x 12:1144 square inches.

A square Hue having a cross-section area of 45 square inches would beapproximately 6.7 inches on a side and the surface area of a section ofHue one brick (4 inches) high would be 6.7 x 4 x 4:1072 square inches.From the above calculations it will be seen that my Hue shape gives 36.8squaie inches more surface in four inches of Hue length than a squareHue having exactly the same cross-section area. This is an increase of34.3% over the square Hue and is of great advantage in absorbing heatfrom the hot gases and allowing the cold air to absorb the heat from thebrick.

Another important advantage oiE my invention over all previous Huestructures is that there are no continuous rows of bricks buttingagainst each other and causing dis tortion of the structure and crackingof the walls when the bricks expand and contract when hea-ted andcooled.

I do not limit my invention to the specilic form shown or to anyparticular size of brick and it will be evident to those skilled in theart that bricks of other sizes, shapes and proportions than abovedescribed can be used to carryout my invention.

I claim: l

l. In a regenerative stove, a Hue structure having vertical Hues, thewalls of said Hues being composed of rectangular brick laid up incourses one upon the other, said Hues be ing cross-shaped on a planeperpendicular to their vertical axes and extending substantially thefull height of the Hue structure.

2. In a regenerative stove a Hue structure having cross-shaped Hues laidup of rectangu-` lar brick the alternate courses of which are identicaland the intermediate courses oilset so that the joints between thebricks of the alternate courses are bonded by the bricks of theintermediate courses. i

3. A Hue structure having vertical Hues, said Hue structure being laidup of rectangular bricks and said Hues being cross-sliaped in horizontalcross-section, said rectangular bricks being laid in courses, saidcourses being so laid that the bricks of alternate courses could beexactly superimposed on each other and the bricks of the intermediatecourses between saidalternate courses could also be exactly superimposedon each other, said al-V on' said iirst named lcourse,theindividualbricks saidsecond'course having. the. same positions relative to` eachother tliatfthe` bricks of-said first named coursehave but the entiresecond ycourse being Voffset relative to saidfirst course so that theHue openings of bothcourses will correspond and the bricks -of saidsecond course will ibond thejoints between-the bricks of said firstcourse; and .i

continuing laying up `alternate courses exactly correspondingtoSaid-Hrst` and second coursesl until the ldesired Hue lengthV isobtained. w

5. A Hue structure having ,Huesv cross-- shaped on a plane perpendicularto their -lon-` bricks of the coursebelow, said cross-shaped Huesextending subst-antiallythe `full height-1 of the Hue structure.

6. A Hue ystructure having Hues `cross-l shaped cna plane perpendicularto `their lone. v gitudinal axes laid up of rectangular bricksnwhicheach individual Hueiis surrounded by the same thickness `of brickassurroundsw Hues laid up of rectangular bricks in which eachV brick isfree from contact with other bricks on at least one end and is free fromContact with other bricks on at least one-half of its total sidesurface.

8. The method of laying up Hue structures p having Hues cross-shaped ona plane perpendicular to their longitudinal axes comprising spacing thebricks so that each brick can expand into a cross-shaped Hue opening.

sisting of parallel double rows of brick threel units long and one unitWide, said parallel rows being composed of two adjacent single e y rowsof brick laid end to end with one unit space between their ends and thebricksv in .each of the two single rows bridging said space between theends of the brick in the adjacentrow, said .parallel double rows ofbrick being spaced apart four units, the space between said paralleldouble rows of brick being occupied by brick two units long and one unitwide, saidk two unit long bricks being laid so as to complete the Wallsof said crossshaped Hues. A

10. VA Hue structure having vertical Hues crosseshaped in horizontalcross-section laid up of superimposed courses of two sizes ofrectangular brcks,`both of said sizes of bricks being of the salme.width and depth, but `the smaller of said. sizesl of bricks beingtwo-thirds asv long; as the larger of said Sizesl of bricks, eachcou-rse being laid up of parallel, spaced 5 apart double rows of saidlarger bricks, the space between saidparallel double rows being occupiedby zigezag rows of said smaller bricks placed with their longitudinalaxesA at ninety degrees to the longitudinal axes of 10 said largerbricks, said parallel double rows of said larger bricks being composedof two single rows of said larger bricks, eachVv brick of each singlerow being spaced apart endwise a distance equal. to the width of abrick, said single rowsbeing'offset so that. each brick of each singlelrow bridges the space between thek ends of the' adjacent bricks in theadjacent single row, and each zigzag row of smaller bricks being laid inso tlf-at a snia-lll brick butts 20 agairnstvthe center of one'side ofeach of saidr larger bricks whichmake up said parallel double rows andother small bricksr lie midway between said? spaced apart dou-ble rowsof said larger bricks with one-'half of each otheir opposite sidesurfaces adjacent the side'surfacesof the adjacent smaller brickswhich*butt against saidv larger bricks;

" ALFRED O. NELSON;

